But Washington faces just that hurdle as it hosts the NATO summit in Chicago on May 20-21.

The summit, to assess Afghanistan's security needs after foreign forces withdraw in 2014, is not a donors conference. But it is likely to be dominated by the question of who will pay the $4 billion a year U.S. and Afghan officials estimate is needed to support Afghan security forces.

The problem: Washington's European NATO allies have little money to spare. With the eurozone in crisis, they are staying quiet about helping underwrite the Afghan army and police.

The United States is expected to cover about two-thirds of the cost, but U.S. officials last month urged their NATO partners to contribute a total of $1.3 billion a year after 2014. The only countries, however, that have pledged so far are Germany at $193 million a year, Britain at $110 million a year, and non-NATO member Australia at $100 million a year.

"When you look at [Anders Fogh] Rasmussen, the secretary-general of NATO, and his report for 2011, his annual report, he really talks a lot about how many of the allies are not meeting commitments to have 2 percent of their GDP spent on the military and defense, and many are under 1 percent even, so it is very clear Europe is broke," Graeme Herd, of the Geneva Center for Security Policy in Switzerland, says. "There is no money."

Herd says European NATO members will not say "no" outright to U.S. pressure. But he expects them to attach strong conditions to any contributions in an effort to lessen their burden.

Test Of Nerves

One reason many European governments cannot simply refuse is public opinion.

Countries with troops or training missions in Afghanistan could risk belittling their own sacrifices if they turn away now.

"There is quite some political willingness to carry part of that burden among the European states," Henning Riecke, of the German Council on Foreign Relations in Berlin, says. "It is obvious that the continuing support of the Afghan security and police forces is the price for an honorable withdrawal of the combat force from Afghanistan."

But even if the Europeans do eventually pledge, their lack of enthusiasm suggests the days of the West shouldering Afghanistan's security costs are ending.

Gareth Price of London's Chatham House says Western capitals want Afghanistan's regional neighbors to help carry the burden.

He predicts tough poker playing in Chicago as some NATO states keep silent to force other countries to come forward.

"People would play their cards close to the chest in the hopes of getting other countries -- maybe from the Gulf, maybe China, from other parts of the world with less economic problems -- to step in and start funding the security side of things," Price says.

Welcome To Join

One key player is India. Price says prospects that country might contribute have grown since New Delhi and Kabul signed a security and trade pact in October.

"There is a recognition that India is popular in Afghanistan, it is doing lots of development work; but it's also benefiting from the security umbrella," Price says. "And the same logic would apply for China with a lot of its investments in mining and so forth."

India and China have not said whether they will help fund Afghan security. Nor has Japan or any of the Gulf states, which Western diplomats are reportedly approaching.

One other potential contributor is Russia. Foreign Minister Sergei Lavrov said in April Moscow was worried the drug trade and terrorism could grow in Afghanistan after the pullout of foreign forces.

NATO chief Rasmussen responded positively by saying that "we would welcome financial contributions from Russia, China, and other countries to ensure a strong sustainable Afghan security force beyond 2014." But so far there are no signs the conversation has gone further.